Thickness is the question homeowners ask most when comparing driveway quotes, and it is a fair one, because it is one of the few specifications that is easy to picture. The short version: around 100mm is the common standard for Australian homes, more is warranted for heavier vehicles, and thickness is only one of the three things that decide whether a driveway lasts.
The typical numbers
- Cars and 4WDs: around 100mm is the widely used residential standard
- Caravans, boats, light trucks: commonly thicker, often with heavier mesh
- Shared driveways on multi-unit sites: usually specified thicker, reflecting the extra traffic
These figures line up with common Australian practice for residential pavements, referenced against AS 3727.1. The right specification for a given driveway comes from the site measure, because the ground, the loads and the layout all feed into it.
Why thickness is not the whole story
A driveway is a system of three parts, and the concrete is only the visible one:
- The ground and base. Concrete is strong in compression but relies on consistent support underneath. Melbourne’s eastern suburbs sit largely on reactive clay that swells and shrinks with the seasons, and driveways poured over poorly prepared ground crack regardless of their thickness. Preparation, with base material brought in and compacted where the ground needs it, is where quality shows.
- The reinforcement. Steel mesh positioned correctly within the slab holds it together as the ground moves. Mesh lying on the dirt at the bottom of the pour contributes little, which is why placement is a better question for a concreter than the mesh grade printed on a quote.
- The concrete itself. Thickness and strength grade, typically 25 MPa for residential work, then finish on top.
A cheap quote often looks identical on paper because thickness is easy to state and the ground work is invisible. Two 100mm driveways can have wildly different lives depending on what sits underneath them, which is exactly why the cost guide recommends comparing quotes on preparation, mesh and concrete grade together.
When thicker is genuinely worth it
Pay for extra depth when the loads justify it:
- A caravan, boat trailer or work truck parking on the slab regularly
- A shared driveway serving multiple homes, where traffic multiplies
- Bin collection or delivery vehicles crossing part of the slab
Going thicker “just to be safe” for a normal family car mostly adds cost without adding useful capacity. The money is usually better spent on a decorative finish or on the drainage details that keep water away from the slab’s underside.
What about the crossover?
The section between your boundary and the road, the crossover, is a separate question: councils specify its construction through their own standard drawings, and a vehicle crossing permit may be required depending on your council. The council’s specification governs that section regardless of what is chosen for the driveway inside the property.
Comparing quotes on more than millimetres
When quotes arrive, put them side by side on four items: site preparation, reinforcement, concrete grade and thickness, and what the drainage plan is. A quote that is vague on the first two but proud of its thickness is telling you where the corners are. Current Melbourne prices by finish are in the cost guide, and a free site measure settles what your block actually needs.
Planning a driveway? See current Melbourne prices or book a free site measure.